Install debug extension variants in CI builds if required

[hhyyrylainen]

right now the builds only install the distributable versions as non-debug versions which seems to work fully for the exported game, but the editor itself complains it cannot load the extension lib to itself. In most cases this will probably not matter as long as Godot doesn't automatically break any scenes. I'm just opening this issue to remember about this caveat as this might affect things if the clouds are re-implemented as a C++ module.